Excessive vibrations from a failed tire contributed to November 2014 landing gear collapse in Edmonton, Alberta

EDMONTON, April 6, 2016 /CNW/ - In its investigation report (A14W0177) released today, the Transportation Safety Board of Canada (TSB) found that excessive vibrations from a failed tire led to the collapse of the right main landing gear on a Jazz Aviation Bombardier DHC-8-402 in Edmonton, Alberta, in November 2014. Three passengers suffered minor injuries.

On 6 November 2014, Jazz Aviation Flight 8481 departed from Calgary International Airport destined for Grande Prairie, Alberta, with 71 passengers and four crew members onboard. During takeoff, one of the tires on the right landing gear failed. The flight was diverted to the Edmonton International Airport. Shortly after touchdown on landing, the right main landing gear collapsed. The right side propeller blades sheared off on impact with the ground and one of the blades penetrated the cabin wall. All passengers and crew evacuated the aircraft. There was no post-occurrence fire.

The investigation determined that a high rotational imbalance was created on the tire that failed during takeoff, resulting in a significant vibration as the tire began to spin up during touchdown. As this vibration was the same or very close to one of the natural frequencies of the right main landing gear, it falsely triggered a sensor within the main landing gear. This resulted in a reduction of hydraulic pressure to the locking mechanism of the landing gear. In this condition, the excessive vibration then caused the mechanical locking system to release, leading the landing gear to collapse. The investigation concluded that the lack of specific requirements for dynamic vibration testing of aircraft components during certification was a risk factor, as similar systems could fail during high-vibration conditions.

Following the occurrence, Jazz Aviation decided to no longer use retreaded tires on the main landing gear of their DHC-8-402 fleet. Further, the operator made changes to its DHC-8-402 operating procedures to reduce stress on the main landing gear tires when manoevring on the ground. Other operators using this aircraft have adopted similar procedures to reduce main landing gear tire stress.

The TSB is an independent agency that investigates marine, pipeline, railway and aviation transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.